linux-kernel - Re: [PATCH] sysfs/file: move NULL checks to where they make sense and can occur

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Message-ID: <4B95FB06.6070906@kernel.org>
Date:	Tue, 09 Mar 2010 16:38:46 +0900
From:	Tejun Heo <tj@...nel.org>
To:	André Goddard Rosa <andre.goddard@...il.com>
CC:	Greg Kroah-Hartman <gregkh@...e.de>, Alex Chiang <achiang@...com>,
	Kenji Kaneshige <kaneshige.kenji@...fujitsu.com>,
	Serge Hallyn <serue@...ibm.com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] sysfs/file: move NULL checks to where they make sense
 and can occur

Hello,

On 03/05/2010 07:46 PM, André Goddard Rosa wrote:
> ... avoiding checking for NULL 2 times in a row when we already have a page.
> 
> It decreases code size:
> text    data     bss     dec     hex filename
> 4246      48    4136    8430    20ee fs/sysfs/file-BEFORE.o
> 4214      48    4136    8398    20ce fs/sysfs/file-AFTER.o
> 
> Signed-off-by: André Goddard Rosa <andre.goddard@...il.com>

Nacked-by: Tejun Heo <tj@...nel.org>

For this level of micro optimization to be meaningful, the code path
should be *really* *really* hot, which none of sysfs code pats are.
Whatever is easier to the eyes wins.

Thanks.

-- 
tejun
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